1. Field of the Invention
The present invention relates to a frame which is used in a filter-press type electrolytic cell formed by alternatively arranging the frames and a diaphragm and fastening them together. More particularly, it relates to a filter-press type diaphragm electrolytic cell used for producing caustic alkali by electrolysis of an aqueous alkali metal salt such as an alkali metal chloride.
2. Description of the Prior Art
In a filter-press type electrolytic cell, frames forming an anode, diaphragms and frames forming a cathode are alternatively arranged and fastened to form anolyte compartments and catholyte compartments which are respectively partitioned by the diaphragms. During electrolysis solutions are fed into and discharged through the frames forming the electrolytic compartments, i.e. the anolyte compartments and catholyte compartments. Frames for conventional electrolytic cells are formed using plates having a central opening and a plurality of surrounding holes. Corresponding holes for the compartments are aligned for communication when the frames are arranged and fastened and grooves are provided for communication of the holes and the electrolytic compartments, as disclosed in U.S. Pat. No. 3,869,375; U.S. Pat. No. 3,017,388 and U.S. Pat. No. 3,933,617. When a solution is fed into an electrolytic compartment or is discharged from it, the solution is passed into the holes communicating through the frames at the bottom of the frames and is fed through the grooves into the electrolytic compartments. The electrolyzed solution or gas is then passed through the grooves into the holes communicating through the frames at the upper portions of the frames and is discharged through the communicating holes. In order to form these grooves and holes on the frames, high processing accuracy and complicated processing operations are required. Such procedures are difficult and expensive. Moreover, it is disadvantages to use block-type frames made of anticorrosive metal from the viewpoints of both expense and weight.